. . "Q-mode factor analysis of geochemical and petrologic data matrices with constant row-sums : an extension of the method of Q-mode factor (vector) analysis to increase its usefulness in geochemical and petrologic investigations" . . . . . . . . . . . . "Additional title page description: An extension of the method of Q-mode factor (vector) analysis to increase its usefulness in geochemical and petrologic investigations." . . . "Extension of method of Q-mode factor (vector) analysis to increase its usefulness in geochemical and petrologic investigations." . "Q-mode factor analysis of geochemical and petrologic data matrices with constant row-sums an extension of the method of Q-mode factor (vector) analysis to increase its usefulness in geochemical and petrologic investigations" . . "Vector analysis." . . . . "Geochemistry Statistical methods." . . "Geological Survey (U.S.)," . . "Petrology Statistical methods." . .